Process for producing a-olefin polymer

ABSTRACT

An α-olefin polymer having extremely high stereoregularity, exhibiting excellent fluidity and containing a decreased amount of catalyst residues in the polymer can be obtained industrially advantageously in accordance with a process for producing an α-olefin polymer which comprises homopolymerizing an α-olefin or copolymerizing two or more α-olefins in the presence of (A) a solid catalyst component comprising magnesium, titanium and a halogen, (B) an organoaluminum compound having a content of hydroaluminum compounds of 0.1% by weight or smaller and (C) an organozinc compound.  
     A block copolymer of propylene comprising a homopolymer portion exhibiting high fluidity and a copolymer portion having a high molecular weight can be obtained in accordance with a process for producing a block copolymer of propylene which comprises polymerizing propylene in the presence of (A) a solid catalyst component comprising a titanium compound and an electron-donating agent, (B) an organoaluminum compound and (C) an organozinc compound to produce crystalline polypropylene and copolymerizing propylene and at least one of ethylene and α-olefins having 4 or more carbon atoms in the presence of the produced crystalline polypropylene.

TECHNICAL FIELD

[0001] The present invention relates to a process for producing anα-olefin polymer and, more particularly, to a process for producing anα-olefin polymer which efficiently provides an olefin polymer havingextremely high stereoregularity and exhibiting excellent fluidity and aprocess for producing a block copolymer of propylene and at least one ofethylene and α-olefins having 4 or more carbon atoms.

BACKGROUND ART

[0002] Since olefin polymers, in particular polypropylene (hereinafterreferred to as PP, occasionally), are crystalline macromolecularcompounds, the olefin polymers exhibit excellent rigidity, tensilestrength, heat resistance, chemical resistance, optical properties andworkability and have low specific gravities. Therefore, the olefinpolymers are widely used in various fields such as injection moldedarticles, containers and packaging materials.

[0003] As the catalyst system for polymerizing α-olefins, many catalystscomprising a solid catalyst component, an organoaluminum compound and,where necessary, an electron-donating compound have been disclosed. Thesolid catalyst component comprises magnesium, titanium, halogen elementsand, where necessary, an electron-donating compound. When an (α-olefinpolymer is produced using such a catalyst, in general, hydrogen is usedas the chain transfer agent. However, this process has a drawback inthat hydrogen must be added in a great amount in order to obtain anα-olefin polymer exhibiting high fluidity and, as the result, thestereoregularity deteriorates or productivity decreases due to adecrease in the monomer concentration in the polymerization field.

[0004] As described above, it is the general practice that the amount ofhydrogen as the chain transfer agent during the polymerization isincreased to improve fluidity of the polymer from the standpoint ofworkability. However, since the resistance of a reactor to pressure islimited, the concentration of the monomer which can be placed into thereactor decreases due to the increase in the concentration of hydrogen.This causes a decrease in the efficiency of the catalyst and an economicdisadvantage arises.

[0005] Thus, the present invention has a first object of providing aprocess for industrially advantageously producing an α-olefin polymerhaving extremely high stereoregularity, exhibiting excellent fluidityand containing a decreased amount of catalyst residues in the polymer.

[0006] A block copolymer of propylene (hereinafter referred to as blockPP, occasionally) is produced, in general, in accordance with a processcomprising producing a homopolymer of propylene by polymerization ofpropylene, followed by producing a copolymer by copolymerization withother momoners. The properties required for block PP are mechanicalproperties derived from the homopolypropylene and impact resistance inan excellent balance. It is also required that the molding property,appearance and elongation are excellent. It is known that suchrequirements can be satisfied by a structure having a homopolymerportion exhibiting excellent fluidity and a copolymer portion having arelatively high molecular weight.

[0007] To enhance fluidity of the homopolymer portion, in general, theamount of hydrogen used as the chain transfer agent is increased duringthe polymerization. However, when hydrogen used in thehomopolymerization in the first stage affects the condition of thecopolymerization in the second stage, in other words, when hydrogen isnot removed or is only partially removed between the first stage and thesecond stage, an increased amount of hydrogen in the stage of thehomopolymerization causes a decrease in the molecular weight of thecopolymer portion due to an increase in the amount of hydrogen in thereactor used in the copolymerization of the second stage and block PPhaving the desired impact resistance cannot be obtained. To improve theimpact resistance of block PP, it is necessary that hydrogen be removedcompletely between the first stage and the second stage and theadditional facilities be installed for this purpose. Moreover, the innerpressure of polymerization apparatuses increases when the amount ofhydrogen is increased during the polymerization. Since the resistance ofthe polymerization apparatuses to pressure is limited, the amount ofhydrogen used during the polymerization is naturally limited. In thiscase, fluidity of the obtained homopolypropylene is limited and block PPhaving the desired properties cannot be obtained.

[0008] When fluidity of the homopolymer portion in block PP is increasedby decomposition of the polymer, the fluidity expected from the meltindex (MI) cannot be obtained. Moreover, a problem arises in thatphysical properties such as impact resistance deteriorate since themolecular weight of the block portion also decreases.

[0009] Therefore, development of a process for producing a homopolymerhaving a high fluidity without a decrease in the molecular weight of thecopolymer portion or an increase in the inner pressure of the reactorhas been desired.

[0010] The present invention has a second object of providing a processfor efficiently producing a block polypropylene comprising a homopolymerportion exhibiting a high fluidity and a copolymer portion having a highmolecular weight.

DISCLOSURE OF THE INVENTION

[0011] As the result of intensive studies by the present inventors toovercome the above problems on the process for producing an α-olefinpolymer, with respect to the first object, it was found that an α-olefinpolymer could be industrially advantageously produced by using anorganozinc compounds as the essential component and an organoaluminumcompound having a small content of hydroaluminum compounds.

[0012] As the first invention, the following processes for producing anα-olefin polymer are provided.

[0013] [1] A process for producing an α-olefin polymer which compriseshomopolymerizing an α-olefin or copolymerizing two or more α-olefins ina presence of (A) a solid catalyst component comprising magnesium,titanium and a halogen, (B) an organoaluminum compound having a contentof hydroaluminum compounds of 0.1% by weight or smaller and (C) anorganozinc compound.

[0014] [2] A process for producing an α-olefin polymer described abovein [1], wherein the solid catalyst component of component (A) furthercomprises an electron-donating agent.

[0015] [3] A process for producing an α-olefin polymer described abovein any of [1] and [2], wherein the organozinc compound of component (C)is an organozinc compound represented by a general formula:

ZnR¹R²

[0016] wherein R¹ and R² each represent a hydrocarbon group having 1 to10 carbon atoms and may represent a same group or different groups.

[0017] [4] A process for producing an α-olefin polymer described abovein any of [1] to [3], wherein the homopolymerization or thecopolymerization is conducted in a further presence of (D) anelectron-donating compound.

[0018] [5] A process for producing an α-olefin polymer described abovein any of [1] to [4], wherein the organoaluminum compound has a contentof hydroaluminum compounds of 0.01% by weight or smaller.

[0019] With respect to the second object, it was found that, when anorganozinc compound was present in the catalyst for polymerization ofpropylene comprising a titanium compound, an electron-donating agent andan organoaluminum compound during the homopolymerization in the firststage, the molecular weight could be reduced to a great degree so that ahomopolymer of propylene exhibiting excellent fluidity could be obtainedand the molecular weight showed almost no decrease in thecopolymerization of the second stage.

[0020] In accordance with this process, it is not necessary that theamount of hydrogen is increased and a homopolymer of propyleneexhibiting desired fluidity can be produced under a condition of a lowpartial pressure of hydrogen, for example, in a slurry process in whicha polymer of propylene is produced while propylene is dissolved in aninert hydrocarbon solvent or in a gas phase process in which a polymerof propylene is produced by reaction of propylene in the gas phase. Whenblock PP is produced, the decrease in the molecular weight of thecopolymer portion in the second stage can be prevented. For example, ina bulk process in which a polymer of propylene is produced in a liquidpropylene, the pressure of hydrogen can be decreased and a homopolymerof propylene exhibiting excellent fluidity can be easily produced usinga small amount of hydrogen even when the resistance to pressure in theprocess is limited.

[0021] As the second invention, the following processes for producing ablock copolymer of propylene are provided.

[0022] [1] A process for producing a block copolymer of propylene whichcomprises polymerizing propylene in a presence of (A) a solid catalystcomponent comprising a titanium compound and an electron-donating agent,(B) an organoaluminum compound and (C) an organozinc compound to producecrystalline polypropylene and copolymerizing propylene and at least oneof ethylene and α-olefins having 4 or more carbon atoms in a presence ofthe produced crystalline polypropylene.

[0023] [2] A process for producing a block copolymer of propylenedescribed above in [1], wherein the solid catalyst component ofcomponent (A) further comprises a magnesium compound.

[0024] [3] A process for producing a block copolymer of propylenedescribed above in any of [1] and [2], wherein the crystallinepolypropylene is produced in a further presence of (D) anelectron-donating compound.

[0025] [4] A process for producing a block copolymer of propylenedescribed above in [3], wherein the electron-donating compound is anorganosilicon compound.

[0026] [5] A process for producing a block copolymer of propylenedescribed above in any of [3] and [4], wherein the solid catalystcomponent of component (A) is obtained by bringing the titanium compoundand a magnesium compound into contact with each other in a presence ofthe electron-donating agent at a temperature of 120 to 150° C. andwashing an obtained product with an inert solvent at a temperature of100 to 150° C.

[0027] [6] A process for producing a block copolymer of propylenedescribed above in [5], wherein the solid catalyst component ofcomponent (A) is obtained by bringing the titanium compound and themagnesium compound into contact with each other in a presence of theelectron-donating agent and a silicon compound at a temperature of 120to 150° C. and washing an obtained product with an inert solvent at atemperature of 100 to 150° C.

[0028] [7] A process for producing a block copolymer of propylenedescribed above in any of [1] to [6], wherein the organozinc compound ofcomponent (C) is an organozinc compound represented by a generalformula:

ZnR¹R²

[0029] wherein R¹ and R² each represent a hydrocarbon group having 1 to10 carbon atoms and may represent a same group or different groups.

[0030] [8] A process for producing a block copolymer of propylenedescribed above in any of [1] to [7], wherein (E) an electron-donatingsubstance is added before or during the copolymerization of propyleneand at least one of ethylene and α-olefins having 4 or more carbonatoms.

THE MOST PREFERRED EMBODIMENT TO CARRY OUT THE INVENTION

[0031] In accordance with the processes for producing an α-olefinpolymer of the present invention (the first invention and the secondinvention), an α-olefin is homopolymerized or copolymerized in thepresence of (A) a solid catalyst component, (B) an organoaluminumcompound, (C) an organozinc compound and, where necessary, (D) anelectron-donating compound.

[0032] In the first invention, (a) magnesium, (b) titanium and (c) ahalogen atom are used as the essential components for (A) the solidcatalyst component and, where necessary, (d) an electron-donating agentis used. An organoaluminum compound having a content of hydroaluminumcompounds of 0.1% by weight or smaller is used as (B) theorgano-aluminum compound.

[0033] In the second invention, (b) a titanium compound and (d) anelectron-donating agent are used as the essential components for (A) thesolid catalyst component and, where necessary, (a) a magnesium compoundand (e) a silicon compound are used. Propylene is polymerized in thepresence of the above components and a crystalline polypropylene isproduced. Then, in the presence of the polypropylene produced above,propylene and at least one of ethylene and α-olefins having 4 or morecarbon atoms are copolymerized and a block copolymer of propylene isproduced. As (E) an electron-donating substance which is added before orduring the copolymerization of propylene and at least one of ethyleneand α-olefins having 4 or more carbon atoms, (d) the electron-donatingagent or (D) the electron-donating compound is used.

[0034] The components of the catalyst for polymerization of olefins inthe present invention and the process for preparing the catalyst will bedescribed in the following.

[0035] (A) The Solid Catalyst Component

[0036] (a) Magnesium Compound

[0037] It is necessary that component (A) of the first inventioncomprises magnesium. Therefore, a magnesium compound is used forpreparation of component (A).

[0038] For component (A) of the second invention, a magnesium compoundis used where necessary.

[0039] The magnesium compound is not particularly limited. Magnesiumcompounds represented by general formula (I):

MgR³R⁴  (I)

[0040] are preferably used.

[0041] In general formula (I), R³ and R⁴ represent a hydrocarbon group,a group represented by OR⁵, R⁵ representing a hydrocarbon group, or ahalogen atom. Examples of the hydrocarbon group represented by R³ and R⁴include alkyl groups having 1 to 12 carbon atoms, cycloalkyl groups,aryl groups and aralkyl groups. Examples of the group represented by OR⁵include groups in which R⁵ represents an alkyl group having 1 to 12carbon atoms, a cycloalkyl group, an aryl group or an aralkyl group.Examples of the halogen atom include chlorine atom, bromine atom, iodineatom and fluorine atom. R³ and R4 may represent the same group ordifferent groups.

[0042] Examples of the magnesium compound represented by general formula(I) include alkylmagnesiums and arylmagnesiums such asdimethylmagnesium, diethylmagnesium, diisopropylmagnesium,dibutylmagnesium, dihexylmagnesium, dioctylmagnesium,ethylbutylmagnesium, diphenylmagnesium and dicyclohexylmagnesium;alkoxymagnesiums and aryloxymagnesiums such as dimethoxymagnesium,diethoxymagnesium, dipropoxymagnesium, dibutoxymagnesium,dihexyloxymagnesium, dioctoxymagnesium, diphenoxymagnesium anddicyclohexyloxymagnesium; alkylmagnesium halides and arylmagnesiumhalides such as ethylmagnesium chloride, butylmagnesium chloride,hexylmagnesium chloride, isopropylmagnesium chloride, isobutylmagnesiumchloride, t-butylmagnesium chloride, phenylmagnesium bromide,benzylmagnesium chloride, ethylmagnesium bromide, butylmagnesiumbromide, phenyl-magnesium chloride and butylmagnesium iodide;alkoxymagnesium halides and aryloxymagnesium halides such asbutoxymagnesium chloride, cyclohexyloxymagnesium chloride,phenoxymagnesium chloride, ethoxy-magnesium bromide, butoxymagnesiumbromide and ethoxymagnesium iodide; and magnesium halides such asmagnesium chloride, magnesium bromide and magnesium iodide.

[0043] Among these magnesium compounds, magnesium halidesalkoxy-magnesiums, alkylmagnesiums and alkylmagnesium halides arepreferable from the standpoint of the polymerization activity and thestereoregularity.

[0044] The above magnesium compounds can be prepared from metallicmagnesium or compound containing magnesium.

[0045] For example, the above magnesium compound can be prepared bybringing metallic magnesium into contact with a halogen and an alcohol.

[0046] Examples of the halogen include iodine, chlorine, bromine andfluorine. Among these halogens, iodine is preferable. Examples of thealcohol include methanol, ethanol, propanol, butanol and cyclohexanol,octanol.

[0047] As another example, the above magnesium compound can be preparedby bringing an alkoxymagnesium represented by Mg(OR⁶)₂, R⁶ representinga hydrocarbon group having 1 to 20 carbon atoms, into contact with ahalide.

[0048] Examples of the halide include silicon compounds of component (e)which will be described later, silicon tetrachloride, silicontetrabromide, tin tetrachloride, tin tetrabromide and hydrogen chloride.Among these compounds, silicon tetrachloride is preferable from thestandpoint of the polymerization activity and the stereoregularity.Preferable examples of the hydrocarbon group represented by R⁶ includealkyl groups such as methyl group, ethyl group, propyl group, isopropylgroup, butyl group, isobutyl group, hexyl group and octyl group;cyclohexyl group; alkenyl groups such as allyl group, propenyl group andbutenyl group; aryl groups such as phenyl group, tolyl group and xylylgroup; and aralkyl groups such as phenetyl group and 3-phenylpropylgroup. Among these groups, alkyl groups having 1 to 10 carbon atoms arepreferable.

[0049] The above magnesium compounds may be supported on a support suchas silica, alumina and polystyrene.

[0050] The above magnesium compound may be used singly or in combinationof two or more and may comprise other elements such as halogens such asiodine, silicon and aluminum or electron-donating agents such asalcohols, ethers and esters.

[0051] (b) Titanium Compound

[0052] In the first and second inventions, it is necessary thatcomponent (A) comprises titanium. Therefore, a titanium compound is usedin the preparation of component (A).

[0053] The titanium compound is not particularly limited. Titaniumcompounds represented by general formula (II):

TiX¹ _(p)(OR⁷)_(4-p)  (II)

[0054] are preferably used.

[0055] In general formula (II), X¹ represents a halogen atom, which ispreferably chlorine atom or bromine atom and more preferably chlorineatom. R⁷ represents a hydrocarbon group which may be a saturated groupor an unsaturated group, may be a linear group, a branched group orcyclic group and may have hetero atoms such as sulfur, nitrogen, oxygen,silicon and phosphorus. It is preferable that R⁷ represents ahydrocarbon group having 1 to 10 carbon atoms, more preferably an alkylgroup, an alkenyl group, a cycloalkenyl group, an aryl group or anaralkyl group and most preferably a linear or branched alkyl group. Whena plurality of groups represented by OR⁷ are present, the plurality ofgroups may be the same with or different from each other. Examples ofthe group represented by R⁷ include methyl group, ethyl group, n-propylgroup, isopropyl group, n-butyl group, sec-butyl group, isobutyl group,n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-decylgroup, allyl group, butenyl group, cyclopentyl group, cyclohexyl group,cyclohexenyl group, phenyl group, tolyl group, benzyl group and phenetylgroup. p represents an integer of 0 to 4.

[0056] Examples of the titanium compound represented by the abovegeneral formula (II) include tetraalkoxytitaniums such astetramethoxytitanium, tetraethoxytitanium, tetra-n-propoxytitanium,tetraisopropoxytitanium, tetra-n-butoxytitanium, tetraisobutoxytitanium,tetracyclohexyloxytitanium and tetraphenoxytitanium; titaniumtetrahalides such as titanium tetrachloride, titanium tetrabromide andtitanium tetraiodide; alkoxytitanium trihalides such as methoxytitaniumtrichloride, ethoxytitanium trichloride, propoxytitanium trichloride,n-butoxytitanium trichloride and ethoxytitanium tribromide;dialkoxytitanium dihalides such as dimethoxytitanium dichloride,diethoxytitanium dichloride, diisopropoxytitanium dichloride,di-n-propoxytitanium dichloride and diethoxytitanium dibromide; andtrialkoxytitanium monohalides such as tiimethoxytitanium chloride,triethoxytitanium chloride, triisopropoxytitanium chloride,tri-n-propoxytitanium chloride and tri-n-butoxytitanium chloride. Amongthese compounds, titanium compounds having a greater number of halogenatoms are preferable and titanium tetrachloride is more preferable fromthe standpoint of the polymerization activity. The titanium compound maybe used singly or in combination of two or more.

[0057] (c) Halogen Atom

[0058] The halogen contained in the solid catalyst component ofcomponent (A) in the first invention is, in general, supplied from themagnesium compound and the titanium compound described above.

[0059] (d) Electron-Donating Agent

[0060] Examples of the electron-donating agent, which is an optionalcomponent in the first invention and the essential component in thesecond invention, include electron-donating agents containing oxygensuch as alcohols, phenols, ketones, aldehydes, carboxylic acids, malonicacid, esters of organic acids and inorganic acids and ethers such asmonoethers, diethers and polyethers; and electron-donating agentscontaining nitrogen such as ammonia, amines, nitriles and isocyanates.Examples of the above organic acid include carboxylic acids and,specifically, malonic acid.

[0061] Among the above electron-donating agents, esters of polybasiccarboxylic acids and polyethers are preferable. Esters of aromaticpolybasic carboxylic acids are more preferable. From the standpoint ofthe polymerization activity, diesters of aromatic dibasic carboxylicacids are most preferable. As the organic group in the ester portion, alinear, branched or cyclic aliphatic hydrocarbon group is preferable.

[0062] Examples of the diester of a dibasic aromatic carboxylic acidinclude dialkyl esters of dicarboxylic acids. Examples of thedicarboxylic acid include phthalic acid, naphthalene-1,2-dicarboxylicacid, naphthalene-2,3-dicarboxylic acid,5,6,7,8-tetrahydronaphthalene-1,2-dicarboxylic acid,5,6,7,8-tetrahydionaphthalene-2,3-dicarboxylic acid,indan-4,5-dicarboxylic acid and indan-5,6-dicarboxylic acid. Examples ofthe alkyl group in the dialkyl ester portion include methyl group, ethylgroup, n-propyl group, isopropyl group, n-butyl group, isobutyl group,t-butyl group, n-pentyl group, 1-methylbutyl group, 2-methylbutyl group,3-methylbutyl group, 1,1-dimethylpropyl group, 1-methylpentyl group,2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group,1-ethylbutyl group, 2-ethylbutyl group, n-hexyl group, cyclohexyl group,n-heptyl group, n-octyl group, n-nonyl group, 2-methylhexyl group,3-methylhexyl group, 4-methylhexyl group, 2-ethylhexyl group,3-ethylhexyl group, 4-ethylhexyl group, 2-methylpentyl group,3-methylpentyl group, 2-ethylpentyl group and 3-ethylpentyl group.

[0063] Among these compounds, diesters of phthalic acid are preferable.It is preferable that the organic group in the ester portion is a linearor branched aliphatic hydrocarbon group having 4 or more carbon atomsfrom the standpoint of the activity and the stereoregularity. Preferableexamples of the diester of phthalic acid include di-n-butyl phthalate,diisobutyl phthalate and di-n-heptyl phthalate.

[0064] Examples of the polyether include compounds represented by thefollowing general formula (III):

[0065] wherein n represents an integer of 2 to 10, R⁸ to R¹⁵ eachrepresent a substituent having at least one element selected fromcarbon, hydrogen, oxygen, halogens, nitrogen, sulfur, phosphorus, boronand silicon, R¹¹ and R¹² may represent the same substituent or differentsubstituents, any substituents among the substituents represented by R⁸to R¹⁵, preferably substituents represented by R¹¹ and R¹², may from aring which is not a benzene ring and the main chain may have atoms otherthan carbon atom. Examples of the polyether compound represented bygeneral formula (III) include 2-(2-ethylhexyl)-1,3-dimethoxypropane,

[0066] 2-isopropyl-1,3-dimethoxypropane, 2-butyl-1,3-dimethoxypropane,

[0067] 2-s-butyl-1,3-dimethoxypropane,2-cyclohexyl-1,3-dimethoxypropane,

[0068] 2-phenyl-1,3-dimethoxypropane, 2-cumyl-1,3-dimethoxypropane,

[0069] 2-(2-phenylethyl)-1,3-dimethoxypropane,

[0070] 2-(2-cyclohexylethyl)-1,3-dimethoxypropane,

[0071] 2-(p-chlorophenyl)-1,3-dimethoxypropane,

[0072] 2-(diphenylmethyl)-1,3-dimethoxy-propane,

[0073] 2-(1-naphthyl)-1,3-dimethoxypropane,

[0074] 2-(2-fluorophenyl)-1,3-dimethoxypropane,

[0075] 2-(1-decahydronaphthyl)-1,3-dimethoxypropane,

[0076] 2-(p-t-butylphenyl)-1,3-dimethoxypropane,

[0077] 2,2-dicyclohexyl-1,3-dimethoxy-propane,

[0078] 2,2-dicyclopentyl-1,3-dimethoxypropane,

[0079] 2,2-diethyl-1,3-dimethoxypropane,2,2-dipropyl-1,3-dimethoxypropane,

[0080] 2,2-diisopropyl-1,3-dimethoxypropane,2,2-dibutyl-1,3-dimethoxypropane,

[0081] 2-methyl-2-propyl-1,3-dimethoxypropane,

[0082] 2-methyl-2-benzyl-1,3-dimethoxypropane,

[0083] 2-methyl-2-ethyl-1,3-dimethoxypropane,

[0084] 2-methyl-2-isopropyl-1,3-dimethoxypropane,

[0085] 2-methyl-2-phenyl-1,3-dimethoxypropane,

[0086] 2-methyl-2-cyclohexyl-1,3-dimethoxypropane,

[0087] 2,2-bis(p-chlorophenyl)-1,3-dimethoxy-propane,

[0088] 2,2-bis(2-cyclohexylethyl)-1,3-dimethoxypropane,

[0089] 2-methyl-2-isobutyl-1,3-dimethoxypropane,

[0090] 2-methyl-2-(2-ethylhexyl)-1,3-dimethoxy-propane,

[0091] 2,2-diisobutyl-1,3-dimethoxypropane,2,2-diphenyl-1,3-dimethoxypropane,

[0092] 2,2-dibenzyl-1,3-dimethoxypropane,

[0093] 2,2-bis(cyclohexyl-methyl)-1,3-dimethoxypropane,

[0094] 2,2-diisobutyl-1,3-diethoxypropane,2,2-diisobutyl-1,3-dibutoxypropane,

[0095] 2-isobutyl-2-isopropyl-1,3-dimethoxy-propane,

[0096] 2-(1-methylbutyl)-2-isopropyl-1,3-dimethoxypropane,

[0097] 2-(1-methylbutyl)-2-s-butyl-1,3-dimethoxypropane,

[0098] 2,2-di-s-butyl-1,3-dimethoxypropane,2,2-di-t-butyl-1,3-dimethoxypropane,

[0099] 2,2-dineopentyl-1,3-dimethoxypropane,

[0100] 2-isopropyl-2-isopentyl-1,3-dimethoxypropane,

[0101] 2-phenyl-2-isopropyl-1,3-dimethoxypropane,

[0102] 2-phenyl-2-s-butyl-1,3-dimethoxypropane,

[0103] 2-benzyl-2-isopropyl-1,3-dimethoxypropane,

[0104] 2-benzyl-2-s-butyl-1,3-dimethoxypropane,

[0105] 2-phenyl-2-benzyl-1,3-dimethoxypropane,

[0106] 2-cyclopentyl-2-isopropyl-1,3-dimethoxypropane,

[0107] 2-cyclopentyl-2-s-butyl-1,3-dimethoxypropane,

[0108] 2-cyclohexyl-2-isopropyl-1,3-dimethoxypropane,

[0109] 2-cyclohexyl-2-s-butyl-1,3-dimethoxypropane,

[0110] 2-isopropyl-2-s-butyl-1,3-dimethoxypropane,

[0111] 2-cyclohexyl-2-cyclohexylmethyl-1,3-dimethoxy-propane,

[0112] 2,3-diphenyl-1,4-diethoxybutane,2,3-dicyclohexyl-1,4-diethoxybutane,

[0113] 2,2-benzyl-1,4-diethoxybutane, 2,3-dicyclohexyl-1,4-diethoxybutane,

[0114] 2,3-diisopropyl-1,4-diethoxybutane,

[0115] 2,2-bis(p-methylphenyl)-1,4-dimethoxybutane,

[0116] 2,3-bis(p-chlorophenyl)-1,4-dimethoxybutane,

[0117] 2,3-bis(p-fluorophenyl) -1,4-dimethoxybutane,

[0118] 2,4-diphenyl-1,5-dimethoxypentane,2,5-diphenyl-1,5-dimethoxyhexane,

[0119] 2,4-diisopropyl-1,5-dimethoxypentane,

[0120] 2,4-diisobutyl-1,5-dimethoxypentane,2,4-diisoamyl-1,5-dimethoxypentane,

[0121] 3-methoxymethyltetrahydrofuran, 3-methoxymethyldioxane,

[0122] 1,3-diisobutoxypropane, 1,2-diisobutoxypropane,1,2-diisobutoxyethane,

[0123] 1,3-diisoamyloxypropane, 1,3-diisoneopentyloxy-ethane,

[0124] 1,3-dineopentyloxypropane,2,2-tetramethylene-1,3-dimethoxy-propane,

[0125] 2,2-pentamethylene-1,3-dimethoxypropane,

[0126] 2,2-hexamethylene-1,3-dimethoxypropane,

[0127] 1,2-bis(methoxymethyl)cyclohexane, 2,8-dioxaspiro[5, 5]undecane,

[0128] 3,7-dioxaspiro[3,3,1]nonane, 3,7-dioxabicyclo-[3,3,0]octane,

[0129] 3,3-diisobutyl-1,5-oxononane, 6,6-diisobutyldioxyheptane,

[0130] 1,1-dimethoxymethylcyclopentane,1,1-bis(dimethoxymethyl)cyclohexane,

[0131] 1,1-bis(methoxymethyl)bicyclo[2,2,1]heptane,

[0132] 1,1-dimethoxymethylcyclo-pentane,

[0133] 2-methyl-2-methoxymethyl-1,3-dimethoxypropane,

[0134] 2-cyclohexyl-2-ethoxymethyl-1,3-diethoxypropane,

[0135] 2-cyclohexyl-2-methoxymethyl-1,3-dimethoxypropane,

[0136] 2,2-diisobutyl-1,3-dimethoxycyclohexane,

[0137] 2-isopropyl-2-isoamyl-1,3-dimethoxycyclohexane,

[0138] 2-cyclohexyl-2-methoxymethyl-1,3-dimethoxycyclohexane,

[0139] 2-isopropyl-2-methoxymethyl-1,3-dimethoxycyclo-hexane,

[0140] 2-isobutyl-2-methoxymethyl-1,3-dimethoxycyclohexane,

[0141] 2-cyclohexyl-2-ethoxymethyl-1,3-diethoxycyclohexane,

[0142] 2-cyclohexyl-2-ethoxymethyl-1,3-dimethoxycyclohexane,

[0143] 2-isopropyl-2-ethoxymethyl-1,3-diethoxycyclohexane,

[0144] 2-isopropyl-2-ethoxymethyl-1,3-dimethoxycyclo-hexane,

[0145] 2-isobutyl-2-ethoxymethyl-1,3-diethoxycyclohexane,

[0146] 2-isobutyl-2-ethoxymethyl-1,3-dimethoxycyclohexane,

[0147] tris(p-methoxyphenyl)phosphine,methylphenylbis(methoxymethyl)silane,

[0148] diphenylbis(methoxymethyl)-silane,

[0149] methylcyclohexylbis(methoxymethyl)silane,

[0150] di-t-butylbis(methoxy-methyl)silane,

[0151] cyclohexyl-t-butylbis(methoxymethyl)silane and

[0152] i-propyl-t-butylbis(methoxymethyl)silane.

[0153] Among these compounds, 1,3-diethers are preferable and

[0154] 2,2-diisobutyl-1,3-dimethoxypropane,

[0155] 2-isopropyl-2-isopentyl-1,3-dimethoxy-propane,

[0156] 2,2-dicyclohexyl-1,3-dimethoxypropane,

[0157] 2,2-bis(cyclohexyl-methyl)-1,3-dimethoxypropane,

[0158] 2-cyclohexyl-2-isopropyl-1,3-dimethoxy-propane,

[0159] 2-isopropyl-2-s-butyl-1,3-dimethoxypropane,

[0160] 2,2-diphenyl-1,3-dimethoxypropane and

[0161] 2-cyclopentyl-2-isopropyl-1,3-dimethoxypropane are morepreferable.

[0162] The above compounds may be used singly or in combination of twoor more.

[0163] (e) Silicon Compound

[0164] In the present invention, a silicon compound represented by thefollowing general formula (IV):

Si(OR¹⁶)_(q)X² _(4-q)  (IV)

[0165] may be used as component (e) in combination with components (a),(b) and (d) described above in the preparation of the solid catalystcomponent, where necessary. In the above general formula (IV), R¹⁶represents a hydrocarbon group, X² represents a halogen atom and qrepresents an integer of 0 to 3. By using the silicon compound, thecatalyst activity and the stereoregularity can be improved and theamount of fine powder in the formed polymer can be decreased.

[0166] In the above general formula (IV), X² represents a halogen atom.Chlorine atom and bromine atom are preferable as the halogen atom. R¹⁶represents a hydrocarbon group which may be a saturated group or anunsaturated group, may be a linear group, a branched group or a cyclicgroup and may have heteroatoms such as sulfur atom, nitrogen atom,oxygen atom, silicon atom and phosphorus atom. It is preferable that theabove hydrocarbon group is a hydrocarbon group having 1 to 10 carbonatoms and more preferably an alkyl group, an alkenyl group, acycloalkenyl group, an aryl group or an aralkyl group. When a pluralityof the group represented by —OR¹⁶ are present, the plurality of groupsmay be the same with or different from each other. Examples of the grouprepresented by R¹⁶ include methyl group, ethyl group, n-propyl group,isopropyl group, n-butyl group, sec-butyl group, isobutyl group,n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-decylgroup, allyl group, butenyl group, cyclopentyl group, cyclohexyl group,cyclohexenyl group, phenyl group, tolyl group, benzyl group and phenetylgroup. q represents an integer of 0 to 3.

[0167] Examples of the silicon compound represented by the above generalformula (IV) include silicon tetrachloride, methoxytrichlorosilane,dimethoxydichlorosilane, trimethoxychlorosilane, ethoxytrichlorosilane,diethoxydichlorosilane, triethoxychlorosilane, propoxytrichlorosilane,dipropoxydichlorosilane and tripropoxychlorosilane. Among thesecompounds, silicon tetrachloride is preferable. The silicon compound maybe used singly or in combination of two or more.

[0168] (Preparation of the Solid Catalyst Component)

[0169] To prepare (A) the solid catalyst component in the firstinvention, (a) the magnesium compound, (b) the titanium compound and,where necessary, (d) the electron-donating agent and (e) the siliconcompound are brought into contact with each other in accordance with aconventional process.

[0170] Examples of the conventional process include processes describedin Japanese Patent Application Laid-Open Nos. Showa 53(1978)-43094,Showa 55(1980)-135102, Showa 55(1980)-135103 and Showa 56(1981)-18606.Specific examples include the following processes. (1) The magnesiumcompound or a complex compound prepared from the magnesium compound andthe electron-donating agent is pulverized in the presence of theelectron-donating agent and, where desired, an auxiliary pulverizingagent and the resultant product is reacted with the titanium compound.(2) A liquid material of the magnesium compound having no reducingability and the titanium compound in the liquid state are reacted witheach other in the presence of the electron-donating agent and a solidtitanium complex compound is precipitated. (3) The product obtained in(1) or (2) described above is reacted with the titanium compound. (4)The product obtained in (1) or (2) described above is reacted with theelectron-donating agent and the titanium compound. (5) The magnesiumcompound or a complex compound prepared from the magnesium compound andthe electron-donating agent is pulverized in the presence of theelectron-donating agent, the titanium compound and, where desired, anauxiliary pulverizing agent and the product is treated with a halogen ora halogen compound.

[0171] Further examples of the process for preparing the solid catalystcomponent of component (A) include processes described in JapanesePatent Application Laid-Open Nos. Showa 56(1981)-166205, Showa57(1982)-63309, Showa 57(1982)-190004, Showa 57(1982)-300407 and Showa58(1982)-47003. The solid catalyst component of component (A) can alsobe prepared by bringing a solid substance, which contains magnesiumsupported on an oxide of an element belonging to any of Groups II to IVof the Periodic Table such as silicon oxide and magnesium oxide or on acomplex oxide containing at least one of oxides of elements belonging toany of the Groups II to IV of the Periodic Table such as silica alumina,into contact with the electron-donating agent and the titanium compoundin a solvent at a temperature in the range of 0 to 200° C. andpreferably in the range of 10 to 150° C. for a time in the range of 2minutes to 24 hours.

[0172] The amount of the titanium compound is, in general, in the rangeof 0.5 to 100 mole and preferably in the range of 1 to 50 mole per 1mole of magnesium in the above magnesium compound. The amount of theelectron-donating agent is, in general, in the range of 0.01 to 10 moleand preferably in the range of 0.05 to 1.0 mole per 1 mole of magnesiumin the above magnesium compound. Silicon tetrachloride may further beadded as the halide.

[0173] The temperature of bringing the components into contact with eachother is, in general, in the range of −20 to 200° C. and preferably inthe range of 20 to 150° C. The time of contact is, in general, in therange of 1 minute to 24 hours and preferably in the range of 10 minutesto 6 hours. The method for bringing the components into contact witheach other is not particularly limited. The components may be broughtinto contact with each other, for example, in the presence of an inertsolvent such as a hydrocarbon or after diluting the components with aninert solvent such as a hydrocarbon. Examples of the inert solventinclude aliphatic hydrocarbons such as n-pentane, isopentane, n-hexane,n-heptane, n-octane and isooctane; aromatic hydrocarbons such asbenzene, toluene and xylene; and mixtures of these solvents.

[0174] It is preferable that the titanium compound is brought intocontact with the other components twice or more so that the titaniumcompound is sufficiently supported on the magnesium compound which playsthe role of the catalyst support. The solid catalyst component obtainedafter the contact may be washed with an inert solvent such as ahydrocarbon. Examples of the inert solvent include the inert solventsdescribed above. The obtained solid product can be kept under a drycondition or in an inert solvent such as a hydrocarbon.

[0175] In the second invention, any solid catalyst component comprising(b) the titanium compound and (d) the electron-donating agent can beused as the solid catalyst component of component (A). It is preferablethat a solid catalyst component is obtained by bringing (b) the titaniumcompound and (a) the magnesium compound into contact with each other inthe presence of (d) the electron-donating agent at a temperature of 120to 150° C., followed by washing the product with an inert solvent at atemperature of 100 to 150° C. It is more preferable that the abovetreatments are conducted in the presence of (e) the silicon compound incombination with (d) the electron-donating agent. The method forbringing the components into contact with each other is not particularlylimited. For example, the components may be brought into contact witheach other in the presence of an inert solvent such as a hydrocarbon orafter diluting the components with an inert solvent such as ahydrocarbon in advance. Examples of the inert solvent include aliphatichydrocarbons such as n-octane, n-decane and ethylcyclohexane; alicyclichydrocarbons; and mixtures of these solvents.

[0176] The titanium compound is used in an amount, in general, in therange of 0.5 to 100 mole and preferably in the range of 1 to 50 mole per1 mole of magnesium in the magnesium compound. When the ratio of theamounts by mole is outside the above range, the catalyst activity isoccasionally insufficient. The electron-donating agent is used in anamount, in general, in the range of 0.01 to 10 mole and preferably inthe range of 0.05 to 1.0 mole per 1 mole of magnesium in the magnesiumcompound. When the ratio of the amounts by mole is outside the aboverange, the catalyst activity and the stereoregularity are occasionallyinsufficient.

[0177] The above components are brought into each other at a temperaturein the range of 120 to 150° C. and preferably in the range of 125 to140° C. after the entire components are mixed together. When thetemperature is outside the above range, the effect of improving thecatalyst activity and the stereoregularity is not sufficientlyexhibited, occasionally. The above components are brought into contactwith each other for a time, in general, in the range of 1 minute to 24hours and preferably in the range of 10 minutes to 6 hours. When asolvent is used, the range in the pressure is various depending on thesolvent and the temperature of the contact. The pressure is, in general,in the range of 0 to 5 MPaG and preferably in the range of 0 to 1 MPaG.From the standpoint of the uniformity and the efficiency of the contact,it is preferable that the mixture is stirred when the components arebrought into contact with each other.

[0178] It is preferable that the titanium compound is brought intocontact with the other components twice or more so that the titaniumcompound is sufficiently supported on the magnesium compound which playsthe role of the catalyst support.

[0179] When a solvent is used in the operation of bringing thecomponents into contact with each other, the solvent is used in anamount, in general, in the range of 5,000 ml or less and preferably inthe range of 10 to 1,000 ml per 1 mole of the titanium compound. Whenthe amount of the solvent is outside the above range, the uniformity ofthe catalyst and the efficiency of the contact occasionally deteriorate.

[0180] It is preferable that the solid catalyst component obtained afterthe components are brought into contact with each other as describedabove is washed with an inert solvent at a temperature in the range of100 to 150° C. and preferably in the range of 120 to 140° C. When thetemperature of washing is outside the above range, the effect ofimproving the catalyst activity and the stereoregularity is notsufficiently exhibited, occasionally. Examples of the inert solventinclude aliphatic hydrocarbons such as n-octane and n-decane; alicyclichydrocarbons such as methylcyclohexane and ethylcyclohexane; aromatichydrocarbons such as toluene and xylene; halogenated hydrocarbons suchas tetrachloroethane and chlorofluoro-carbons; and mixtures of thesesolvents. Among these solvents, aliphatic hydrocarbons are preferable.

[0181] The process of washing is not particularly limited. Decantationand filtration are preferable. The amount of the inert solvent, the timeof the washing and the number of repeated washing are not particularlylimited. In general, the solvent is used in an amount in the range of100 to 100,000 ml and preferably in the range of 1,000 to 50,000 ml per1 mole of the magnesium compound and the washing is conducted, ingeneral, for a time in the range of 1 minute to 24 hours and preferablyin the range of 10 minutes to 6 hours. When the conditions are outsidethe above ranges, the washing is occasionally insufficient.

[0182] The range of the pressure in the washing is various depending onthe solvent and the temperature of the washing. The pressure is, ingeneral, in the range of 0 to 5 MPaG and preferably in the range of 0 to1 MPaG. It is preferable that the mixture containing the solid catalystcomponent is stirred during the washing of the solid catalyst componentfrom the standpoint of the uniformity and the efficiency of the washing.

[0183] The obtained solid catalyst component can be kept under a drycondition or in an inert solvent such as a hydrocarbon.

[0184] (B) Organoaluminum Compound

[0185] The organoaluminum compound of component (B) used as theessential component in the first and second inventions is notparticularly limited. For example, an aluminum compound having an alkylgroup represented by the following general formula (VIII):

R²⁹ _(m)Al(OR³⁰)_(n)X³ _(3-n-m)  (VIII)

[0186] can be preferably used. In the above general formula, R²⁹ and R³⁰each represent an alkyl group having 1 to 8 carbon atoms and preferably1 to 4 carbon atoms, X³ represents a halogen atom, m represents a numberin the range of 0<m≦3, preferably 2 or 3 and most preferably 3 and nrepresents a number in the range of 0≦n<3 and preferably 0 or 1.

[0187] Examples of the organoaluminum compound include trialkylaluminumssuch as trimethylaluminum, triethylaluminum, triisopropylaluminum,triisobutylaluminum and trioctylaluminum; dialkylaluminum monohalidessuch as diethylaluminum monochloride, diisopropylaluminum monochloride,diisobutylaluminum monochloride and dioctylaluminum monochloride; andalkylaluminum sesquihalides such as ethylaluminum sesquichloride. Amongthe above organo-aluminum compounds, trialkylaluminums having a loweralkyl group having 1 to 5 carbon atoms are preferable andtrimethylaluminum, triethylaluminum, tripropylaluminum andtriisobutylaluminum are more preferable. The organoaluminum compound maybe used singly or in combination of two or more.

[0188] In the first invention, the content of hydroaluminum compounds in(B) the organoaluminum compound is 0.1% by weight or smaller andpreferably 0.01% by weight or smaller. When the content of thehydroaluminum compounds exceeds 0.1% by weight, α-olefin polymersexhibiting excellent fluidity and having a decreased amount of catalystresidues in the polymer cannot be produced industrially advantageously.

[0189] (C) Organozinc Compound

[0190] As component (C) which is the essential component in the firstand second inventions, an organozinc compound represented by the generalformula:

ZnR¹R²

[0191] is preferable. In the general formula, R¹ and R² each represent ahydrocarbon group having 1 to 10 carbon atoms and may represent the samegroup or different groups, Examples of the hydrocarbon group having 1 to10 carbon atoms include methyl group, ethyl group, various types ofpropyl groups, various types of butyl groups, various types of hexylgroups and various types of octyl groups. Examples of the alkylzinccompound include dimethylzinc, diethylzinc, di-n-propylzinc,diispropylzinc and di-n-butylzinc and diisobutylzinc. Among thesealkylzinc compounds, dimethylzinc and diethylzinc are preferable.

[0192] (D) Electron-Donating Compound

[0193] As the electron-donating compound which is added, wherenecessary, during the polymerization in the first and second invention,organosilicon compounds having the Si—O—C bond, compounds havingnitrogen, compounds having phosphorus and compounds having oxygen can beused. From the standpoint of the polymerization activity and thestereoregularity, it is preferable that the organosilicon compoundshaving the Si—O—C bond are used among the above compounds.

[0194] Examples of the organosilicon compounds having the Si—O—C bondinclude tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane,

[0195] tetraisobutoxysilane, trimethylmethoxysilane,trimethylethoxysilane,

[0196] triethylmethoxysilane, triethylethoxysilane,

[0197] ethylisopropyldimethoxy-silane, propylisopropyldimethoxysilane,

[0198] diisopropyldimethoxysilane, diisobutyldimethoxysilane,

[0199] isopropylisobutyldimethoxysilane, di-t-butyldimethoxysilane,

[0200] t-butylmethyldimethoxysilane, t-butylethyl-dimethoxysilane,

[0201] t-butylpropyldimethoxysilane, t-butylisopropyl-dimethoxysilane,

[0202] t-butylbutyldimethoxysilane, t-butylisobutyldimethoxy-silane,

[0203] t-butyl(s-butyl)dimethoxysilane, t-butylamyldimethoxysilane,

[0204] t-butylhexyldimethoxysilane, t-butylheptyldimethoxysilane,

[0205] t-butyloctyl-dimethoxysilane, t-butylnonyldimethoxysilane,

[0206] t-butyldecyldimethoxy-silane,

[0207] t-butyl(3,3,3-trifluoromethylpropyl)dimethoxysilane,

[0208] cyclohexyl-methyldimethoxysilane, cyclohexylethyldimethoxysilane,

[0209] cyclohexyl-propyldimethoxysilane,cyclopentyl-t-butyldimethoxysilane,

[0210] cyclohexyl-t-butyldimethoxysilane, dicyclopentyldimethoxysilane,

[0211] dicyclohexyl-dimethoxysilane,bis(2-methylcyclopentyl)dimethoxysilane,

[0212] bis(2,3-dimethylcyclopentyl)dimethoxysilane,diphenyldimethoxysilane,

[0213] phenyl-triethoxysilane, methyltrimethoxysilane,ethyltrimethoxysilane,

[0214] propyl-trimethoxysilane, isopropyltrimethoxysilane,

[0215] butyltrimethoxysilane, isobutyltrimethoxysilane,t-butyltrimethoxysilane,

[0216] s-butyltrimethoxy-silane, amyltrimethoxysilane,isoamyltrimethoxysilane,

[0217] cyclopentyl-trimethoxysilane, cyclohexyltrimethoxysilane,

[0218] norbornanetrimethoxy-silane, indenyltrimethoxysilane,

[0219] 2-methylcyclopentyltrimethoxysilane,

[0220] cyclopentyl(t-butoxy)dimethoxysilane,isopropyl(t-butoxy)dimethoxysilane,

[0221] t-butyl(isobutoxy)dimethoxysilane,t-butyl(t-butoxy)dimethoxysilane,

[0222] thexyltriemthoxysilane, thexylisopropoxydimethoxysilane,

[0223] thexyl(t-butoxy)dimethoxysilane, thexylmethyldimethoxysilane,

[0224] thexylethyl-dimethoxysilane, thexylisopropyldimethoxysilane,

[0225] thexylcyclopentyl-dimethoxysilane, thexylmyristyldimethoxysilaneand

[0226] thexylcyclohexyl-dimethoxysilane.

[0227] The above organosilicon compound may be used singly or incombination of two or more.

[0228] Silicon compounds represented by the following general formula(V):

[0229] can also be used. In the above general formula, R¹⁸ to R²⁰ eachrepresent hydrogen atom or a hydrocarbon group and may represent thesame group or different groups, adjacent groups represented by any ofR¹⁸ to R²⁰ may be bonded to each other and form a ring, R²¹ and R²² eachrepresent a hydrocarbon group and may represent the same group ordifferent groups, adjacent groups represented by R²¹ and R²² may bebonded to each other and form a ring, R²³ and R²⁴ each represent analkyl group having 1 to 20 carbon atoms and may represent the same groupor different groups, m represents an integer of 2 or greater and nrepresents an integer of 2 or greater.

[0230] Examples of the atom and the group represented by R¹⁸ to R²⁰ ingeneral formula (V) include hydrogen atom; linear hydrocarbon groupssuch as methyl group, ethyl group and n-propyl group; branchedhydrocarbon groups such as isopropyl group, isobutyl group, t-butylgroup and thexyl group; saturated cyclic hydrocarbon groups such ascyclobutyl group, cyclopentyl group and cyclohexyl group; andunsaturated cyclic hydrocarbon groups such as phenyl group andpentamethylphenyl group. Among these groups, hydrogen atom and linearhydrocarbon groups having 1 to 6 carbon atoms are preferable andhydrogen atom, methyl group and ethyl group are more preferable.

[0231] Examples of the group represented by R²¹ and R²² include linearhydrocarbon groups such as methyl group, ethyl group and n-propyl group;branched hydrocarbon groups such as isopropyl group, isobutyl group,t-butyl group and thexyl group; saturated cyclic hydrocarbon groups suchas cyclobutyl group, cyclopentyl group and cyclohexyl group; andunsaturated cyclic hydrocarbon groups such as phenyl group andpentamethylphenyl group. The groups represented by R²¹ and R²² may bethe same with or different from each other. Among these groups, hydrogenatom and linear hydrocarbon groups having 1 to 6 carbon atoms arepreferable and hydrogen atom, methyl group and ethyl group are morepreferable.

[0232] Examples of the group represented by R²³ and R²⁴ include linearor branched alkyl groups such as methyl group, ethyl group, n-propylgroup, isopropyl group, n-butyl group, isobutyl group, sec-butyl group,t-butyl group, n-pentyl group, n-hexyl group and n-octyl group. Thegroups represented by R²³ and R²⁴ may be the same with or different fromeach other. Among these groups, linear hydrocarbon groups having 1 to 6carbon atoms are preferable and methyl group is more preferable.

[0233] Examples of the silicon compound represented by general formula(V) include neopentyl-n-propyldimethoxysilane,

[0234] neopentyl-n-butyldimethoxysilane,neopentyl-n-pentyldimethoxysilane,

[0235] neopentyl-n-hexyldimethoxysilane,neopentyl-n-hexyldimethoxysilane,

[0236] isobutyl-n-propyldimethoxysilane,isobutyl-n-butyldimethoxysilane,

[0237] isobutyl-n-pentyldimethoxysilane, isobutyl-n-hexydimethoxysilane,

[0238] isobutyl-n-heptyldimethoxysilane,

[0239] 2-cyclohexylpropyl-n-propyldimethoxysilane,

[0240] 2-cyclohexylbutyl-n-propyldimethoxysilane,

[0241] 2-cyclohexylpentyl-n-propyl-dimethoxysilane,

[0242] 2-cyclohexylhexyl-n-propyldimethoxysilane,

[0243] 2-cyclohexylheptyl-n-propyldimethoxysilane,

[0244] 2-cyclopentylpropyl-n-propy-ldimethoxysilane,

[0245] 2-cyclopentylbutyl-n-propyldimethoxysilane,

[0246] 2-cyclopentylpentyl-n-propyldimethoxysilane,

[0247] 2-cyclopentylhexyl-n-propyl-dimethoxysilane,

[0248] 2-cyclopentylheptyl-n-propyldimethoxysilane,

[0249] isopentyl-n-propyldimethoxysilane,isopentyl-n-butyldimethoxysilane,

[0250] isopentyl-n-pentyldimethoxysilane,isopentyl-hexyldimethoxysilane,

[0251] isopentyl-n-hexyldimethoxysilane,isopentyl-n-heptyldimethoxysilane,

[0252] isopentyl-isobutyldimethoxysilane,isopentylneopentyldimethoxysilane,

[0253] diisopentyl-dimethoxysilane, diisoheptyldimethoxysilane,

[0254] diisohexyldimethoxysilane and dicyclopentyldimethoxysilane.Preferable examples of the compound includeneopentyl-n-propyldimethoxysilane, neopentyl-n-pentyl-dimethoxysilane,isopentylneopentyldimethoxysilane, diisopentyl-dimethoxysilane,diisoheptyldimethoxysilane, diisohexyldimethoxysilane anddicyclopentyldimethoxysilane. More preferable examples of the compoundinclude neopentyl-n-pentyldimethoxysilane, diisopentyl-dimethoxysilaneand dicyclopentyldimethoxysilane.

[0255] The silicon compound represented by general formula (V) can besynthesized in accordance with any desired process. A typical route ofsynthesis is shown in the following:

[0256] In this route of synthesis, material compound [1] is commerciallyavailable or can be obtained in accordance with a conventional processof alkylation or halogenation. The organosilicon compound represented bygeneral formula (V) can be obtained in accordance with the known processof the Grignard reaction with compound [1].

[0257] The above organosilicon compound may be used singly or incombination of two or more.

[0258] Examples of the compound having nitrogen include2,6-disubstituted piperidines such as 2,6-diisopropylpiperidine,2,6-diispropyl-4-methylpiperidine andN-methyl-2,2,6,6-tetramethylpiperidine; 2,5-disubstituted azolidinessuch as 2,5-diisopropylazolidine andN-methyl-2,2,5,5-tetramethylazolidine; substituted methylenediaminessuch as N,N,N′,N′-tetramethylmethylenediamine andN,N,N′,N′-tetraethyl-methylenediamine; and substituted imdazolidinessuch as 1,3-dibenzyl-imidazolidine and1,3-dibenzyl-2-phenylimidazolidine.

[0259] Examples of the compound having phosphorus include esters ofphosphorous acid such as triethylphosphite, tri-n-propoylphosphite,triisopropylphosphite, tri-n-butylphosphite, triisobutylphosphite,diethyl-n-butylphosphite and diethylphenylphosphite.

[0260] Examples of the compound having oxygen include 2,6-disubstitutedtetrahydrofurans such as 2,2,6,6-tetramethyltetrahydrofuran and2,2,6,6-tetraethyltetrahydrofuran; dimethoxymethane derivatives such as1,1-dimethoxy-2,3,4,5-tetrachloropentadiene and 9,9-dimethoxyfluoreneand diphenyldimethoxymethane; and polyethers described in the above for(d) the electron-donating agent.

[0261] As the organosilicon compound used where necessary in the secondinvention, for example, organosilicon compounds of the electron-donatingcompound represented by the following general formula (VI):

Si(OR²⁵)_(q)R²⁶ _(4-q)  (VI)

[0262] can be used. In the above general formula (VI), R²⁵ and R²⁶ eachrepresent a hydrocarbon group and may represent the same group ordifferent groups and q represents an integer of 0 to 3.

[0263] In the above general formula (VI), R²⁵ and R²⁶ each represent ahydrocarbon group and may represent the same group or different groups,as described above. The hydrocarbon group may be a saturated group or anunsaturated group, may be a linear group, a branched group or a cyclicgroup and may have a hetero atom such as sulfur, nitrogen, oxygen,silicon and phosphorus. It is preferable that the hydrocarbon group is ahydrocarbon having 1 to 10 carbon atoms and more preferably an alkylgroup, an alkenyl group, a cycloalkenyl group, an aryl group or anaralkyl group. When a plurality of groups represented by —OR²⁵ arepresent, the plurality of groups may be the same with or different fromeach other. Examples of the group represented by R²⁵ and R²⁶ includemethyl group, ethyl group, n-propyl group, isopropyl group, n-butylgroup, sec-butyl group, isobutyl group, n-pentyl group, n-hexyl group,n-heptyl group, n-octyl group, n-decyl group, allyl group, butenylgroup, cyclopentyl group, cyclohexyl group, cyclohexenyl group, phenylgroup, tolyl group, benzyl group and phenetyl group. q represents aninteger of 0 to 3.

[0264] Examples of the organosilicon compound represented by generalformula (VI) include the compounds described as the examples of theorganosilicon compound having Si—O—C bond.

[0265] (Process for Producing an α-Olefin Polymer)

[0266] The amount of the catalyst used in the first invention is notparticularly limited. In general, the solid catalyst component ofcomponent (A) is used in an amount such that the amount of the titaniumatom is in the range of 0.00005 to 1 mmole per 1 liter of the reactionvolume. The organoaluminum compound of component (B) is used in such anamount that the ratio of the amounts by atom of aluminum to titanium is,in general, in the range of 1 to 5,000 and preferably in the range of 10to 500. When the ratio of the amounts by atom is outside the aboverange, the catalyst activity is occasionally insufficient. When theelectron-donating compound such as the organosilicon compound ofcomponent (D) is used, the electron-donating compound is used in such anamount that the ratio of the amounts by mole of (D) theelectron-donating compound to (B) the organoaluminum compound is, ingeneral, in the range of 0.001 to 5.0, preferably in the range of 0.01to 2.0 and more preferably in the range of 0.05 to 1.0. When the ratioof the amounts by mole is outside the above range, sufficient catalystactivity and stereoregularity are not obtained, occasionally.

[0267] In the first invention, an α-olefin represented by generalformula (VII):

R²⁷—CH═CH₂  (VII)

[0268] is used.

[0269] In the above general formula (VII), R²⁷ represents hydrogen atomor a hydrocarbon group which may be a saturated group or an unsaturatedgroup. Examples of the α-olefin include ethylene, propylene, 1-butene,1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 3-methyl-1-pentene,4-methyl-1-pentene, vinylcyclohexane, butadiene, isoprene andpiperylene. The α-olefin may be used singly or in combination of two ormore. Among the above α-olefins, ethylene and propylene are preferable.

[0270] In the first invention, the polymerization is conducted in thepresence of (A) the above solid catalyst component, (B) the aboveorganoaluminum compound, (C) the above organozinc compound and, wherenecessary, (D) the above electron-donating compound. The polymerizationmay be conducted in the gas phase or in the liquid phase. Thepolymerization may also be conducted by bringing the monomer componentinto contact with the above catalyst components while the catalystcomponents are suspended in a slurry in an inert solvent such asn-butane, n-pentane, isopentane, n-hexane, n-heptane, n-octane,cyclohexane, toluene and xylene or by bringing the monomer into contactwith the catalyst components in the gas phase. The polymerization mayalso be conducted in the liquid propylene.

[0271] The amount of (C) the organozinc compound is not particularlylimited as long as the effect of the present invention can be exhibited.

[0272] In the first invention, where desired, the olefin may bepreliminarily polymerized and the major polymerization is conductedthereafter so that the desired polymerization activity, stereoregularityand form of the polymer powder can be obtained. When the preliminarypolymerization is conducted, the olefin is preliminarily polymerized, ingeneral, at a temperature of 100° C. or lower and preferably in therange of −10 to 80° C. at a pressure in the range of the ordinarypressure to about 5 MPaG in the presence of a catalyst prepared bymixing (A) the above solid catalyst component, (B) the aboveorganoaluminum compound and, where necessary, (C) the above organozinccompound and/or (D) the above electron-donating compound in specificrelative amounts in an inert solvent such as n-butane, n-pentane,isopentane, n-hexane, n-heptane, n-octane, cyclohexane, toluene andxylene and a product of preliminary polymerization (hereinafter,referred to as a preliminary polymerized catalyst, occasionally) isobtained. Hydrogen may be present or absent in the preliminarypolymerization. It is preferable that the amount of the preliminarilypolymerized olefin is 0.01 to 5,000 g and more preferably 0.05 to 1,000g per 1 g of (A) the above solid catalyst component.

[0273] Examples of the olefin used for the preliminary polymerizationinclude olefins described as the examples of the α-olefin represented bygeneral formula (VII). The olefin may be used singly or in combinationof two or more. Among the above olefins, ethylene and propylene arepreferable.

[0274] When the preliminary polymerization is conducted, the componentsdescribed above are mixed together. The preliminary polymerization maybe conducted by introducing the olefin directly after mixing thecomponents or after mixing the components and aging the resultantmixture for 0.2 to 3 hours.

[0275] It is preferable that the major polymerization of the olefin isconducted in the presence of the preliminarily polymerized catalyst,component (B), component (C) and component (D) since the polymerizationactivity and the stereoregularity are improved and an olefin polymerexhibiting excellent fluidity can be obtained. The amounts of thepreliminary polymerized catalyst obtained as described above, component(B), component (C) and component (D) used in the major polymerizationare as follows. The preliminarily polymerized catalyst is used in anamount such that the amount of titanium atom in the preliminarilypolymerized catalyst is, in general, in the range of 0.00005 to 1 mmoleper 1 liter of the volume of the reaction mixture. The organoaluminumcompound of component (B) is used in an amount such that the ratio ofthe amounts by atom of aluminum to titanium is, in general, in the rangeof 1 to 5,000 and preferably in the range of 1 to 300. When theelectron-donating compound such as the organosilicon compound is used ascomponent (D), the electron-donating compound is used in an amount suchthat the ratio of the amounts by mole of (D) the electron-donatingcompound to (B) the organoaluminum compound is, in general, in the rangeof 0.001 to 5.0 and preferably in the range of 0.01 to 2.0. When theratio of the amounts by mole is outside the above range, sufficientcatalyst activity and stereoregularity are not obtained, occasionally.

[0276] Component (C) is used in an amount such that the ratio of theamounts by atom of zinc to titanium is, in general, in the range of 1 to1,000 and preferably 10 to 500. When the ratio of the amounts by atom isoutside the above range, the catalyst activity is occasionallyinsufficient.

[0277] The form of the major polymerization is not particularly limitedand any of the solution polymerization, the slurry polymerization, thegas phase polymerization and the bulk polymerization may be conducted.Any of the batch polymerization and the continuous polymerization may beconducted. The polymerization may also be conducted in accordance with atwo-stage polymerization or a multi-stage polymerization underconditions different between the stages.

[0278] The reaction conditions are as follows. The pressure of thepolymerization is not particularly limited. The pressure is suitablyselected, in general, in the range of the atmospheric pressure to 8 MPaGand preferably in the range of 0.2 to 5 MPaG from the standpoint of thepolymerization activity. The temperature is suitably selected, ingeneral, in the range of 0 to 200° C., preferably in the range of 20 to150° C. and more preferably in the range of 40 to 100° C. The time ofpolymerization cannot be generally decided since the time is variousdepending on the temperature of polymerization of the olefin used as thematerial. The time of polymerization is, in general, in the range of 5minutes to 20 hours and preferably in the range of 10 minutes to 10hours.

[0279] The molecular weight can be adjusted by adding a chain transferagent such as hydrogen gas. An inert gas such as nitrogen gas may bepresent.

[0280] In the first invention, the polymerization can be conducted byusing the components in various orders. For example, component (A),component (B) and component (D) are mixed in specific relative amountsand the components are brought into contact with each other. Thepreliminary polymerization may be conducted, where desired, andcomponent (C) is brought into contact with the above mixture or with theobtained preliminarily polymerized catalyst. Propylene is introduceddirectly after the addition of component (C) and the majorpolymerization is conducted. Alternatively, after component (A),component (B) and component (D) are brought into contact with eachother, the mixture is aged for 0.2 to 3 hours. The preliminarypolymerization may be conducted, where desired, and component (C) isbrought into contact with the above mixture or with the preliminarilypolymerized catalyst. Propylene is introduced after the addition ofcomponent (C) and the major polymerization is conducted. The abovecatalyst components may be supplied after being suspended in an inertsolvent or in the olefin used as the raw material

[0281] In the first invention, the after-treatment of the polymerizationcan be conducted in accordance with a conventional process. In the gasphase polymerization, the polymer powder released from thepolymerization reactor may be treated with nitrogen gas passing throughthe powder to remove the olefin and the like remaining in the powder or,where desired, may be pelletized by an extruder. A small amount of wateror an alcohol may be added during the above treatments so that thecatalyst is completely inactivated. In the bulk polymerization, afterthe polymerization is completed, the monomer is completely separatedfrom the polymer released from the polymerization reactor and thepolymer is pelletized.

[0282] Typical examples of the polymer of olefins obtained in accordancewith the first invention include polymers of propylene. The polymer ofpropylene may be a homopolymer of propylene or a copolymer of propylenewith ethylene and/or an α-olefin having 4 or more carbon atoms. Thecopolymer of propylene may be a random copolymer or a block copolymer.Examples of the homopolymer of propylene include homopolymers ofpropylene having extremely high stereoregularity such as a fraction ofthe (mmmm) pentad exceeding 95% by mole as measured in accordance with¹³C-NMR and exhibiting high fluidity such as a melt flow rate, ingeneral, in the range of 20 to 1,000 g/10 minutes and preferably in therange of 50 to 500 g/10 minutes as measured in accordance with themethod of ASTM D1238 under the condition of the temperature of 230° C.and the load of 21.18 N.

[0283] (Process for Producing a Block Copolymer of Propylene)

[0284] In the second invention, it is preferable that a preliminarilypolymerized catalyst is prepared and then the major polymerization isconducted from the standpoint of the polymerization activity, thestereoregularity and the form of powder of the polymer. Thepreliminarily polymerized catalyst can be prepared by bringing (A) theabove solid catalyst component, (B) the above organoaluminum and,preferably, (D) the above electron-donating compound into contact withan olefin such as propylene, ethylene, 1-butene and 1-hexene. The olefinmay be used singly or in combination of two or more. It is preferablethat the preliminary polymerization is conducted in an inert solventsuch as n-butane, n-pentane, isopentane, n-hexane, n-heptane, n-octane,cyclohexane, toluene and xylene. It is preferable that the preliminarypolymerization is conducted at a temperature, in general, in the rangeof 80° C. or lower, preferably in the range of −10 to 60° C. and morepreferably in the range of 0 to 50° C. at a pressure in the range of theatmospheric pressure to about 5 MPaG. The amount of the preliminarilypolymerized olefin is preferably 0.05 to 50 g and more preferably 0.1 to10 g per 1 g of (A) the above solid catalyst component.

[0285] When the preliminary polymerization is conducted, component (A),component (B) and component (D) may be mixed in specific relativeamounts and brought into contact with each other. The preliminarypolymerization may be conducted by introducing the olefin directly aftermixing component (A), component (B) and component (D) or after mixingcomponent (A), component (B) and component (D) and aging the resultantmixture for 0.2 to 3 hours.

[0286] In the first stage, propylene is homopolymerized in the presenceof the preliminarily polymerized catalyst obtained above, (B) theorganoaluminum compound, (C) the organozinc compound and, preferably,(D) the electron-donating compound. In the second stage, a comonomercomponent is introduced so that the copolymerization of propylene withthe comonomer takes place. Block PP can be obtained in this manner. Inthe homopolymerization of the first stage, a homopolymer of propyleneexhibiting fluidity such as a melt flow rate in the range of 20 to 1,000g/10 minutes and preferably in the range of 50 to 500 g/10 minutes asmeasured in accordance with the method of ASTM D1238 at the temperatureof 230° C. under the load of 21.2 N (2.16 kgf) can be obtained.

[0287] The comonomer is at least one of ethylene and α-olefins having 4or more carbon atoms. Examples of the α-olefin having 4 or more carbonatoms include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene,1-decene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-dodecene,1-tetradecene, 1-hexadecene, 1-octadecene and 1-eicosene. The α-olefinmay be used singly or in combination of two or more.

[0288] In the second invention, it is preferable that the homopolymerportion (the homopolymer of propylene) has an intrinsic viscosity in therange of 0.5 to 1.5 dl/g and more preferably in the range of 0.5 to 1.2dl/g as measured in decalin at 135° C. so that sufficient fluidity canbe obtained. It is preferable that the copolymer portion has anintrinsic viscosity in the range of 1.0 to 10 dl/g and more preferablyin the range of 1.5 to 10 dl/g so that sufficient impact strength ismaintained.

[0289] The homopolymerization of propylene may be conducted in separateseveral stages in accordance with the object. When the condition ischanged in the copolymerization, degassing is conducted where necessaryand the relative amounts of the components and the amount of hydrogencan be changed. It is preferable that (E) an electron-donating substanceis added in the production of block PP since a decrease in the molecularweight by addition of the organozinc compound can be substantiallyprevented by adding the electron-donating substance before or during thecopolymerization with the comonomer. As (E) the electron-donatingsubstance, the compounds described as the examples of (b) theelectron-donating agent and (D) the electron-donating compound can beused. Among these compounds, alcohols are preferable and ethanol is morepreferable. In this case, it is preferable that the amount of (E) theelectron-donating substance is in the range of about 0.01 to 1.5 moleper 1 mole of the total of (B) the organoaluminum compound and (C) theorganozinc compound which are used in the homopolymerization ofpropylene. When the amount of the electron-donating substance exceeds1.5 mole, the activity of the catalyst exceedingly decreases,occasionally.

[0290] The polymerization can be conducted in the gas phase or in theliquid phase. The polymerization may also be conducted by bringing themonomer component into contact with the preliminarily polymerizedcatalyst while the catalyst is suspended as a slurry in an inert solventsuch as n-butane, n-pentane, isopentane, n-hexane, n-heptane, n-octane,cyclohexane, toluene and xylene or by bringing the monomer into contactwith the catalyst in the gas phase. The polymerization may also beconducted in the liquid propylene. Any of the batch polymerization andthe continuous polymerization may be conducted. The polymerization mayalso be conducted in accordance with a two-stage polymerization or amulti-stage polymerization under conditions different between thestages.

[0291] The amounts of the catalyst components used in the secondinvention are not particularly limited. The solid catalyst component ofcomponent (A) is used in an amount such that the amount of titanium atomis, in general, 0.00005 to 1 mmole per 1 liter of the volume of thereaction mixture. The organoaluminum compound of component (B) is usedin an amount such that the ratio of the amounts by atom of aluminum totitanium is, in general, in the range of 1 to 1,000 and preferably inthe range of 10 to 500. When the ratio of the amounts is outside theabove range, the catalyst activity becomes occasionally insufficient.The organozinc compound of component (C) is used in an amount such thatthe ratio of the amounts by atom of aluminum to zinc is, in general, inthe range of 1 to 10,000, preferably in the range of 1 to 1,000 and morepreferably in the range of 1 to 500. When the ratio of the amounts byatom is smaller than 1, the effect of component (C) is not exhibited,occasionally. When the ratio of the amounts by atom exceeds 10,000, thecatalyst activity is occasionally insufficient. (D) Theelectron-donating compound is used in an amount such that the ratio ofthe amounts by mole of (D) the electron-donating compound to (B) theorganoaluminum compound is, in general, in the range of 0.001 to 5.0,preferably in the range of 0.01 to 2.0 and more preferably in the rangeof 0.05 to 1.0. When the ratio of the amounts by mole is outside theabove range, sufficient catalyst activity and stereoregularity are notobtained, occasionally. However, the ratio of the amounts by mole ofcomponent (D) to component (B) can be further decreased when thepreliminary polymerization is conducted.

[0292] The reaction conditions are as follows. The pressure is notparticularly limited. From the standpoint of the polymerizationactivity, the pressure is suitably selected, in general, in the range ofthe atmospheric pressure to 10 MPaG and the polymerization temperatureis suitably selected, in general, in the range of −80 to 180° C. andpreferably in the range of 20 to 150° C.

[0293] In the second invention, the after-treatment of thepolymerization can be conducted in accordance with a conventionalprocess. In the gas phase polymerization, the polymer powder releasedfrom the polymerization reactor may be treated with nitrogen gas passingthrough the powder to remove the olefin and the like remaining in thepowder or, where desired, may be pelletized by an extruder. A smallamount of water or an alcohol may be added during the above treatmentsso that the catalyst is completely inactivated. In the bulkpolymerization, after the polymerization is completed, the monomer iscompletely separated from the polymer released from the polymerizationreactor and the polymer is pelletized.

EXAMPLES

[0294] The present invention will be described more specifically withreference to examples in the following. However, the present inventionis not limited to the examples.

[0295] In Examples 1 to 6 and Comparative Examples 1 to 3 which areexamples of the first invention, the physical properties and theanalytical values were obtained in accordance with the followingmethods.

[0296] (1) Intrinsic viscosity (η): A polymer was dissolved into decalinand the intrinsic viscosity was measured at 135° C.

[0297] (2) Melt flow rate (MFR): The melt flow rate was measured inaccordance with the method of ASTM D1238 at 230° C. under a load of21.18 N.

[0298] (3) Stereoregularity (the fraction of the (mmmm) pentad): Apolymer was dissolved in a mixed solvent containing1,2,4-trichlorobenzene and heavy benzene in a ratio of the amounts byvolume of 90:10. The signal of methyl group was obtained in accordancewith the method of complete decoupling of proton at 130° C. using a¹³C-NMR apparatus (manufactured by NIPPON DENSHI Co., Ltd.; LA-500) andthe fraction of the (mmmm) pentad was obtained from the obtained value.The fraction of the isotactic (mmmm) pentad used in the presentinvention means the fraction of the isotactic pentad in the pentad unitsin the molecular chain of polypropylene obtained from the ¹³C nuclearmagnetic resonance spectrum, which was proposed by A. Zambelli et al. in“Macromolecules, 6, 925 (1973)”. For the assignment of the peaks in theobtained ¹³C nuclear magnetic resonance spectrum, the assignmentproposed by A. Zambelli et al. in “Macromolecules, 8, 687 (1975)” wasused.

[0299] (4) Content of aluminum hydride in an organoaluminum compound: Anorganoaluminum compound was hydrolyzed and the formed gas was analyzedin accordance with the gas chromatography.

[0300] In the examples of the first invention, the following threeorganoaluminum compounds were used. Triethylaluminum A: the content ofaluminum hydride was 0.6% by weight. Triethylaluminum B: the content ofaluminum hydride was 0.05% by weight. Triethylaluminum C: the content ofaluminum hydride was 0.004% by weight.

[0301] The content of aluminum hydride was adjusted by distillingcommercial triethylaluminum and, where necessary, mixingtriethylaluminum obtained after the distillation with that before thedistillation.

[0302] In Examples 7 to 11 and Comparative Examples 4 and 5 which areexamples of the second invention, the intrinsic viscosity [η], thecontent of the fraction soluble in p-xylene and the content of ethylenein the fraction soluble in p-xylene were obtained in accordance with thefollowing methods.

[0303] (1) Intrinsic viscosity [η]: A homopolymer portion or a fractionsoluble in p-xylene was dissolved in decalin and the intrinsic viscositywas measured at 135° C.

[0304] (2) The content of the fraction soluble in p-xylene: The amountof the fraction soluble in p-xylene at 25° C. was obtained in accordancewith the following method.

[0305] A sample of a block copolymer of propylene and ethylene in anamount of 5±0.05 g was accurately weighed and placed into a 1,000 mleggplant-shape flask. After 1±0.05 g of BHT (an antioxidant) was addedinto the flask, a stirrer and 700±10 ml of p-xylene were placed into theflask and a condenser was attached to the eggplant-shape flask. Theflask was heated for 120±30 minutes in an oil bath at 140±5° C. whilethe stirrer was rotated and the sample was dissolved in p-xylene. Thecontent of the flask was poured into a 1,000 ml beaker and cooled understirring by the stirrer while the beaker was left standing. After thecontent of the beaker was stirred until the temperature reached the roomtemperature (25° C.) (8 hours or longer), the precipitates were removedwith a metal net. The filtrate was filtered again with a filter paperand poured into 2,000 ml of methanol placed in a 3,000 ml beaker. Theobtained liquid was left standing under stirring by a stirrer for 2hours or longer. The precipitates were separated with a metal net, driedin the air for 5 hours or longer and then dried in a vacuum drier at100±5° C. for 240 to 270 minutes and the fraction soluble in p-xylenewas recovered.

[0306] When the amount by weight of the sample is expressed by A g andthe amount of the recovered fraction soluble in p-xylene is expressed byC g, the content of the fraction soluble in p-xylene in the sample iscalculated as: W (% by weight)=100×C/A.

[0307] (3) Content of ethylene unit in the fraction soluble in p-xylene:The content of the ethylene unit in the fraction soluble in p-xylene wasmeasured in accordance with ¹³C-NMR as follows:

[0308] The fraction soluble in p-xylene was examined in accordance with¹³C-NMR and the intensities by area of I(Tδδ), I(Tβδ), I(Sγδ), I(Sδδ),I(Tββ), I(Sβδ) and I(Sββ) of the peaks assigned to carbons of Tδδ, Tβδ,Sγδ, Sδδ, Tββ, Sβδ and Sββ, respectively, were obtained. Using theobtained intensities by area, fractions of f_(EEE), f_(EPE), f_(PPE),f_(PPP), f_(PEE) and f_(PEP) of the triads EEE, EPE, PPE, PPP, PEE andPEP, respectively, were calculated in accordance with the followingequations:

f _(EEE) =[I(Sδδ)/2+I(Sγδ)/4]/T

f _(EPE) =I(Tδδ)/T

f _(PPE) =I(Tβδ)/T

f _(PPP) =I(Tββ)/T

f _(PEE) =I(Sβδ)/T

f _(PEP) =I(Sββ)/T

[0309] wherein T=I(Sδδ)/2+I(Sγδ)/4+I(Tδδ) +I(Tβδ)+I(Tββ)+I(Sβδ)+I(Sββ).

[0310] The content of the ethylene unit (% by mole) was calculated fromthe fractions obtained above in accordance with the following equation:Content  of  ethylene  unit  (%  by  mole) = 100{f_(EEE) + 2(f_(PEE) + f_(EPE))/3 + (f_(PEP) + f_(PEE))/3}

[0311] The content of the ethylene unit (% by weight) was calculated inaccordance with the following equation:Content  of  ethylene  unit  (%  by  weight) =   [28  E  t  (%  by  mole)/{28  Et(%  by  mole) + 42(100 − E  t(%  by  mole)}] × 100

[0312] wherein the content of the ethylene unit (% by mole) is expressedby Et(% by mole).

[0313] For the measurement of ¹³C-NMR, the fraction soluble in p-xylenewas dissolved in a mixed solvent containing 1,2,4-trichlorobenzene andheavy benzene in a ratio of the amounts by volume of 90:10 and themeasurement was conducted in accordance with the method of completedecoupling of proton at 130° C. using a ¹³C-NMR apparatus (manufacturedby NIPPON DENSHI Co., Ltd.; LA-500).

Example 1

[0314] (1) Preparation of a Solid Catalyst Component

[0315] After a three-necked flask having an inner volume of 0.5 litersand equipped with a stirrer was purged with nitrogen, 60 ml ofdehydrated n-octane and 16 g of diethoxymagnesium were placed into theflask. The resultant mixture was heated at 40° C. and 2.4 ml of silicontetrachloride was added. After the resultant mixture was stirred for 20minutes, 1.6 ml of di-n-butyl phthalate was added. The obtained solutionwas heated at 80° C. and 77 ml of titanium tetrachloride was addeddropwise. The temperature inside the flask was raised to 125° C. and theoperation of contact was conducted under stirring for 2 hours. After thestirring was stopped, solid substances were precipitated and thesupernatant liquid was removed. Then, 100 ml of dehydrated n-octane wasadded. The resultant mixture was heated at 125° C. under stirring andkept at this condition for 1 minute. After the stirring was stopped,solid substances were precipitated and the supernatant liquid wasremoved. This operation of washing was repeated 7 times. Then, 122 ml oftitanium tetrachloride was added. The temperature inside the flask wasraised to 125° C. and the second operation of contact was conducted.Then, the operation of washing with dehydrated n-octane was repeated 6times and a solid catalyst component was obtained.

[0316] (2) Preparation of a Product of Preliminary Polymerization

[0317] After a three-necked flask having an inner volume of 0.5 litersand equipped with a stirrer was purged with nitrogen, a slurry indehydrated n-octane containing the above solid catalyst component wasadded in an amount such that the mass of the solid substance was 12 gand the temperature was kept at 25° C. After 1.5 g of triethylaluminum Bwas added and the resultant mixture was stirred for 15 minutes, 1.1 g ofdicyclopentyldimethoxysilane was added. The temperature of the resultantfluid was raised to 50° C. and propylene gas was introduced into thefluid at the rate of 50 ml/minute for 2 hours. Then, the introduction ofpropylene gas was stopped and the temperature was slowly lowered to 25°C. over 40 minutes. After the stirring was stopped, solid substanceswere precipitated and the supernatant liquid was removed. Then, 100 mlof dehydrated n-octane was added and the resultant fluid was stirred for1 minute. After the stirring was stopped, solid substances wereprecipitated and the supernatant liquid was removed. This operation ofwashing was repeated 5 times and a product of preliminary polymerizationwas obtained.

[0318] (3) Polymerization

[0319] Into an autoclave made of stainless steel, having an inner volumeof 5 liters and equipped with an inlet tube for materials and a stirrer,30 g of homopolypropylene (the intrinsic viscosity: 0.96 dl/g) wasplaced as the seed powder. After the inside of the autoclave wassufficiently dried under a reduced pressure, the temperature inside theautoclave was raised to 80° C. under stirring. Hydrogen was introducedso that the partial pressure of hydrogen was adjusted to 0.6 MPa. Then,propylene was introduced and the total pressure was adjusted to 2.8MPaG. Into the inlet tube for materials, 7.6 ml of triethylaluminum B(the content of aluminum hydride: 0.05% by weight), 0.5 ml ofdiethylzinc and 20 ml of dehydrated n-heptane were placed. Thesematerials were then introduced into the autoclave utilizing thedifference in the pressure between the inlet tube and the autoclave.Into the inlet tube for materials, 20 ml of dehydrated n-heptane, 0.4mmole of triethylaluminum B, 1.0 mmole of dicyclopentyldimethoxysilaneand the product of preliminary polymerization in an amount such that theamount of titanium was 0.02 mmole were placed. These materials were thenintroduced into the autoclave utilizing the difference in the pressurebetween the inlet tube and the autoclave. The polymerization was allowedto proceed for 1 hour while propylene was additionally introduced in amanner such that the total pressure was kept constant. Then, thetemperature was lowered and the pressure was released. The product wastaken out and dried under a reduced pressure and a polymer of propylenewas obtained. The obtained results are shown in Table 1.

Example 2

[0320] The same procedures as those conducted in Example 1 wereconducted except that diethylzinc was used in an amount of 1.0 mmole.The results are shown in Table 1.

Example 3

[0321] The same procedures as those conducted in Example 1 wereconducted except that triethylaluminum C (the content of aluminumhydride: 0.004% by weight) was used. The results are shown in Table 1.

Example 4

[0322] The same procedures as those conducted in Example 3 wereconducted except that diethylzinc was used in an amount of 1.0 mmole.The results are shown in Table 1.

Comparative Example 1

[0323] The same procedures as those conducted in Example 1 wereconducted except that triethylaluminum A (the content of aluminumhydride: 0.6% by weight) was used. The results are shown in Table 1.

[0324] In Examples 1 and 3 and Comparative Example 1, the same amount ofdiethylzinc was used but the obtained MFR as the indicator of fluiditywas different. Sufficient fluidity was not obtained in ComparativeExample 1 in contrast to the fluidity obtained in Examples 1 and 3. Asshown in the result of Comparative Example 2, fluidity of the samedegree as those in Examples 1 and 3 could be obtained when the amount ofdiethylzinc was increased to twice the amount of Comparative Example 1.However, the amount of zinc residues contained in the polymer wasconsidered to be greater than those in the polymers of Examples 1 and 3when the yield was taken into consideration. Thus, it is shown that theprocesses in Examples 1 and 3 were more excellent from the standpoint ofachieving both of the decrease in the zinc residues in the polymer andthe excellent fluidity.

Comparative Example 2

[0325] The same procedures as those conducted in Comparative Example 1were conducted except that diethylzinc was used in an amount of 1.0mmole. The results are shown in Table 1.

[0326] In Examples 2 and 4 and Comparative Example 2, the same amount ofdiethylzinc was used but the obtained MFR as the indicator of fluiditywas different. Sufficient fluidity was not obtained in ComparativeExample 2 in contrast to the fluidity obtained in Examples 1 and 3.

Example 5

[0327] An autoclave made of stainless steel, having an inner volume of 1liter and equipped with an inlet tube for materials and a stirrer wassufficiently dried and 360 ml of n-heptane, 2 mmole of triethylaluminumB, 1 mmole of diethylzinc and 0.25 mmole of dicyclopentyldimethoxysilanewere placed into the autoclave. The temperature was raised to 80° C. andhydrogen was introduced so that the partial pressure of hydrogen wasadjusted to 0.2 MPa. Then, propylene was introduced and the totalpressure was adjusted to 0.8 MPaG. Into the inlet tube for materials, 20ml of dehydrated n-heptane and the product of preliminary polymerizationin an amount such that the amount of titanium was 0.02 mmole wereplaced. These materials were then introduced into the autoclaveutilizing the difference in the pressure between the inlet tube and theautoclave. The polymerization was allowed to proceed for 1 hour whilepropylene was additionally introduced in a manner such that the totalpressure was kept constant. The polymerization was terminated byintroducing 20 ml of methanol from the inlet tube for materials. Then,the temperature was lowered and the pressure was released. The contentwas taken out into 2 liters of methanol and, after filtration and dryingin vacuo, a polymer was obtained. The results are shown in Table 1.

Example 6

[0328] The same procedures as those conducted in Example 5 wereconducted except that triethylaluminum C (the content of aluminumhydride: 0.004% by weight) was used. The results are shown in Table 1.

Comparative Example 3

[0329] The same procedures as those conducted in Example 1 wereconducted except that triethylaluminum A (the content of aluminumhydride: 0.6% by weight) was used. The results are shown in Table 1.

[0330] In Examples 5 and 6 and Comparative Example 3, the same amount ofdiethylzinc was used but the obtained intrinsic viscosity as theindicator of the molecular weight was different. In Comparative Example3, sufficient fluidity could not be obtained since the intrinsicviscosity was greater, i.e., the molecular weight was greater, thanthose in Examples 5 and 6. TABLE 1 Example Comparative Example 1 2 3 4 56 1 2 3 Content of aluminum 0.05 0.05 0.004 0.004 0.05 0.004 0.6 0.6 0.6hydride (% by weight) Amount of diethylzinc 0.5 1.0 0.5 1.0 1.0 1.0 0.51.0 1.0 (mmole) Yield (g) 570 590 670 640 57 68 680 830 51 Intrinsicviscosity (dl/g) 1.04 0.91 1.00 0.89 0.59 0.55 1.11 1.03 1.67 Fluidity(MFR) (g/10 min) 93 142 85 143 60 86 Stereoregularity (mmmm) 98.2 98.398.2 98.2 98.2 98.4 98.1 98.4 98.1 (% by mole)

Example 7

[0331] Into an autoclave made of stainless steel, having an inner volumeof 5 liters and equipped with an inlet tube for materials and a stirrer,30 g of homopolypropylene was placed as the seed powder. After theinside of the autoclave was sufficiently dried under a reduced pressure,the temperature inside the autoclave was raised to 80° C. understirring. Hydrogen and propylene were introduced so that the partialpressure of hydrogen was adjusted to 0.6 MPa and the total pressure wasadjusted to 2.8 MPaG. Into the inlet tube for materials, 20 mmole ofdehydrated n-heptane, 3.6 mmole of triethylaluminum and 1.0 mmole ofdiethylzinc were placed. These materials were then introduced into theautoclave utilizing the difference in the pressure between the inlettube and the autoclave. Into the inlet tube for materials, 20 ml ofdehydrated n-heptane, 0.4 mmole of triethylaluminum, 1.0 mmole ofdicyclopentyldimethoxysilane and the preliminarily polymerized catalystobtained in Example 1 in an amount such that the amount of titanium was0.02 mmole were placed. These materials were then introduced into theautoclave utilizing the difference in the pressure between the inlettube and the autoclave. The polymerization was allowed to proceed for 1hour while propylene was additionally introduced in a manner such thatthe total pressure was kept constant (the first stage polymerization).After the temperature was lowered and the pressure was released, a smallamount of the product was taken out. The pressure in the autoclave wasreduced and the temperature was raised to 60° C. Hydrogen was added sothat the pressure was adjusted to 0.1 MPaG. A mixed gas containingethylene and propylene in amounts such that the ratio of the amounts bymole of ethylene to propylene was 3.5:6.5 was introduced and the totalpressure was adjusted to 1.5 MPaG. The polymerization was allowed toproceed for 45 minutes (the second stage polymerization) Then, thetemperature was lowered and the pressure was released. The product wastaken out and dried in vacuo and a block copolymer of propylene wasobtained. The obtained results are shown in Table 2.

Example 8

[0332] The same procedures as those conducted in Example 7 wereconducted except that diethylzinc was used in an amount of 6.0 mmole.The results are shown in Table 2.

Comparative Example 4

[0333] The same procedures as those conducted in Example 7 wereconducted except that diethylzinc was not used. The results are shown inTable 2.

Example 9

[0334] The same procedures as those conducted in Example 7 wereconducted except that hydrogen was not introduced in the second stagepolymerization. The results are shown in Table 2.

Example 10

[0335] The same procedures as those conducted in Example 8 wereconducted except that hydrogen was not introduced in the second stagepolymerization. The results are shown in Table 2.

Example 11

[0336] The same procedures as those conducted in Example 9 wereconducted except that 1.0 mmole of ethanol was added at the start of thesecond stage polymerization. The results are shown in Table 2.

Comparative Example 5

[0337] The same procedures as those conducted in Example 9 wereconducted except that diethylzinc was not used. The results are shown inTable 2. TABLE 2 Com- Com- para- para- tive tive Exam- Exam- Example pleExample ple 7 8 4 9 10 11 5 Amount of diethylzinc 1.0 6.0 0.0 1.0 6.01.0 0.0 (mmole) Activity (tg/g-Ti) 810 820 680 1050 1150 780 790Intrinsic viscosity of 1.04 0.90 1.17 1.00 0.94 1.01 1.24 homopolymerportion (dl/g) (Portion soluble in p-xylene) Intrinsic viscosity (dl/g)2.35 2.18 2.80 4.17 4.09 5.72 5.68 Amount of soluble portion 18.4 18.118.3 18.6 14.8 12.6 15.3 (% by weight) Content of ethylene unit 29.029.7 29.7 30.5 27.4 31.4 28.7 (% by weight)

Industrial Applicability

[0338] In accordance with the first invention of the present invention,an α-olefin polymer having extremely high stereoregularity, exhibitingexcellent fluidity and containing a decreased amount of catalystresidues can be obtained industrially advantageously.

[0339] In accordance with the second invention, a block copolymer ofpropylene which has a homopolymer portion exhibiting excellent fluidityand a copolymer portion having a high molecular weight can beefficiently produced.

1. A process for producing an α-olefin polymer which compriseshomopolymerizing an α-olefin or copolymerizing two or more α-olefins ina presence of (A) a solid catalyst component comprising magnesium,titanium and a halogen, (B) an organoaluminum compound having a contentof hydroaluminum compounds of 0.1% by weight or smaller and (C) anorganozinc compound.
 2. A process for producing an α-olefin polymeraccording to claim 1, wherein the solid catalyst component of component(A) further comprises an electron-donating agent.
 3. A process forproducing an α-olefin polymer according to claim 1, wherein theorganozinc compound of component (C) is an organozinc compoundrepresented by a general formula: ZnR¹R² wherein R¹ and R² eachrepresent a hydrocarbon group having 1 to 10 carbon atoms and mayrepresent a same group or different groups:
 4. A process for producingan α-olefin polymer according to claim 1, wherein the homopolymerizationor the copolymerization is conducted in a further presence of (D) anelectron-donating compound.
 5. A process for producing an α-olefinpolymer according to claim 1, wherein the organoaluminum compound has acontent of hydroaluminum compounds of 0.01% by weight or smaller.
 6. Aprocess for producing a block copolymer of propylene which comprisespolymerizing propylene in a presence of (A) a solid catalyst componentcomprising a titanium compound and an electron-donating agent, (B) anorganoaluminum compound and (C) an organozinc compound to producecrystalline polypropylene and copolymerizing propylene and at least oneof ethylene and α-olefins having 4 or more carbon atoms in a presence ofthe produced crystalline polypropylene.
 7. A process for producing ablock copolymer of propylene according to claim 6, wherein the solidcatalyst component of component (A) further comprises a magnesiumcompound.
 8. A process for producing a block copolymer of propyleneaccording to claim 6, wherein the crystalline polypropylene is producedin a further presence of (D) an electron-donating compound.
 9. A processfor producing a block copolymer of propylene according to claim 8,wherein the electron-donating compound is organosilicon compound.
 10. Aprocess for producing a block copolymer of propylene according to claim8, wherein the solid catalyst component of component (A) is obtained bybringing the titanium compound and a magnesium compound into contactwith each other in a presence of the electron-donating agent at atemperature of 120 to 150° C. and washing an obtained product with aninert solvent at a temperature of 100 to 150° C.
 11. A process forproducing a block copolymer of propylene according to claim 10, whereinthe solid catalyst component of component (A) is obtained by bringingthe titanium compound and the magnesium compound into contact with eachother in a presence of the electron-donating agent and a siliconcompound at a temperature of 120 to 150° C. and washing an obtainedproduct with an inert solvent at a temperature of 100 to 150° C.
 12. Aprocess for producing a block copolymer of propylene according to claims6, wherein the organozinc compound of component (C) is an organozinccompound represented by a general formula: ZnR¹R² wherein R¹ and R² eachrepresent a hydrocarbon group having 1 to 10 carbon atoms and mayrepresent a same group or different groups.
 13. A process for producinga block copolymer of propylene according to claims 6, wherein (E) anelectron-donating substance is added before or during thecopolymerization of propylene and at least one of ethylene and α-olefinshaving 4 or more carbon atoms.